Avulsion fracture of the anterior superior iliac crest following autograft for anterior lumbar fusion: case report and literature review.

Avulsion fracture of the anterior superior iliac crest (ASIC) following autogenous bone grafting for anterior lumbar fusion (ALF) is an extremely rare complication. We describe a very rare case of avulsion fracture of the ASIC following autograft for ALF in a revision surgery for treating lumbar tuberculosis. A 68-year-old woman with lumbar tuberculosis underwent posterior debridement and posterior iliac crest bone graft fusion; however, her lumbar tuberculosis recurred 9 months after surgery. She then underwent a lumbar revision surgery, including removal of the posterior instrumentation and debridement, followed by anterior L2 corpectomy, debridement, anterior left iliac crest bone graft fusion, and internal fixation. When walking for the first time on postoperative day 3, she experienced a sharp, sudden-onset pain in the anterior iliac crest harvest area. X-ray revealed an avulsion fracture of the ASIC. Considering her failure to respond to conservative treatment for one week and large displacement of the fracture ends, an open reduction and internal fixation surgery was scheduled. Her pain symptoms were significantly relieved after the operation. Although rare, fracture of the ASIC following autograft for ALF should not be ignored. Fracture of the ASIC is usually treated conservatively. Additional surgical treatment is required only when intractable pain fails to respond to conservative treatment or when there is a large displacement of fracture ends that are not expected to heal spontaneously.

Comparison of different anesthesia modalities during percutaneous kyphoplasty of osteoporotic vertebral compression fractures.

Local and general anesthesia are the main techniques used during percutaneous kyphoplasty (PKP); however, both are associated with adverse reactions. Monitored anesthesia with dexmedetomidine may be the appropriate sedative and analgesic technique. Few studies have compared monitored anesthesia with other anesthesia modalities during PKP. Our aim was to determine whether monitored anesthesia is an effective alternative anesthetic approach for PKP. One hundred sixty-five patients undergoing PKP for osteoporotic vertebral compression fractures (OVCFs) were recruited from a single center in this prospective, non-randomized controlled study. PKP was performed under local anesthesia with ropivacaine (n = 55), monitored anesthesia with dexmedetomidine (n = 55), and general anesthesia with sufentanil/propofol/sevoflurane (n = 55). Perioperative pain was assessed using a visual analogue score (VAS). Hemodynamic variables, operative time, adverse effects, and perioperative satisfaction were recorded. The mean arterial pressure (MAP), heart rate, VAS, and operative time during monitored anesthesia were significantly lower than local anesthesia. Compared with general anesthesia, monitored anesthesia led to less adverse anesthetic effects. Monitored anesthesia had the highest perioperative satisfaction and the lowest VAS 2 h postoperatively; however, the monitored anesthesia group had the lowest MAP and heart rate 2 h postoperatively. Based on better sedation and analgesia, monitored anesthesia with dexmedetomidine achieved better patient cooperation, a shorter operative time, and lower adverse events during PKP; however, the MAP and heart rate in the monitored anesthesia group should be closely observed after surgery.

Kinematic MRI Analysis of Reducible Atlantoaxial Dislocation for Decompression.

BACKGROUND: Many doctors ignored the possibility that there is still a spinal cord compression (SCC) need for decompression after atlantoaxial reduction. Reduction can be achieved on kinematic magnetic resonance imaging (MRI); thus, we want to analyze the role of kinematic MRI in reducible atlantoaxial dislocation and make a preoperative decision whether to perform decompression. METHODS: 36 patients with atlantoaxial reduction on preoperative kinematic MRI in extension postures were enrolled retrospectively. Grouping was based on the condition of SCC after atlantoaxial reduction preoperatively. Group A: patients with SCC after atlantoaxial reduction on dynamic cervical MRI were treated with C1 laminectomy for decompression and atlantoaxial fixation. Group B: patients with no significant SCC, according to dynamic MRI, underwent only atlantoaxial fixation. Clinical outcomes were evaluated using JOA score for spinal cord function. Radiological outcomes were assessed by measuring spinal cord diameter on MRI. RESULTS: The mean follow-up time was 17.1 months. Postoperative JOA score and percentage of SCC in both groups were significantly better than its preoperative score. There were no significant statistical differences in the JOA score at 12 months after surgery and the JOA improvement rate between two groups. All patients in the two groups had a lower percentage of SCC on preoperative extension MRI, compared with neutral MRI. No significant statistical differences in the spinal decompression improvement rate were observed between the two groups. CONCLUSIONS: Decompression should be performed in patients who still have significant SCC on preoperative kinematic MRI. Kinematic MRI could be used to assess SCC and decide whether to perform decompression preoperatively.

Reliability and application of the new morphological classification system for chronic symptomatic osteoporotic thoracolumbar fracture.

BACKGROUND: We propose a new classification system for chronic symptomatic osteoporotic thoracolumbar fracture (CSOTF) based on fracture morphology. Research on CSOTF has increased in recent years; however, the lack of a standard classification system has resulted in inconvenient communication, research, and treatment. Previous CSOTF classification studies exhibit different symptoms, with none being widely accepted. METHODS: Imaging data of 368 patients with CSOTF treated at our hospital from January 2010 to June 2017 were systematically analyzed to develop a classification system. Imaging examinations included dynamic radiography, computed tomography scans, and magnetic resonance imaging. Ten investigators methodically studied the classification system grading in 40 cases on two occasions, examined 1 month apart. Kappa coefficients (κ) were calculated to determine intraobserver and interobserver reliability. Based on the radiographic characteristics, the patients were divided into 5 types, and different treatments were suggested for each type. Clinical outcome evaluation included using the visual analog score (VAS), the Oswestry disability index (ODI), and the American Spinal Injury Association (ASIA) impairment scale. RESULTS: The new classification system for CSOTF was divided into types I-V according to whether the CSOTF exhibited dynamic instability, spinal stenosis or kyphosis deformity. Intra- and interobserver reliability were excellent for all types (κ = 0.83 and 0.85, respectively). The VAS score and ODI of each type were significantly improved at the final follow-up compared with those before surgery. In all patients with neurological impairment, the ASIA grading after surgery was significantly improved compared with that before surgery (P < 0.001). CONCLUSIONS: The new classification system for CSOTF demonstrated excellent reliability in this initial assessment. The treatment algorithm based on the classification can result in satisfactory improvement of clinical efficacy for the patients of CSOFT.

Spontaneous Fusion After Cervical Disc Arthroplasty: A Case Report and Literature Review.

OBJECTIVE: To report a rare case of spontaneous fusion (SF) following cervical disc arthroplasty (CDA), to review the related literature, and to propose a new measure to prevent it. METHODS: The course of a patient with SF is described here. The potential causes, risk factors, and preventive measure of SF after CDA published in previous studies have also been reviewed and discussed. RESULTS: A 63-year-old man presented with a 6-month history of progressive neck pain and developed left C-7 radiculopathy 4 years ago. Magnetic resonance imaging revealed disc herniation at the C6-C7 levels resulting in compression of the left C-7 nerve root. The patient underwent CDA at the C6-C7 levels, during which a PRESTIGE cervical disc device was implanted. He failed to follow-up regularly as recommended postoperatively because he was completely free from the pain in his neck and left upper limb. Four years later, he was readmitted with a 2-month history of occasional neck stiffness. Plain radiographs indicated complete radiographic fusion of the C6-C7 levels with trabecular bone bridging surrounding the cervical disc prosthesis, and dynamic imaging showed no motion. He was seen at regular follow-up visits for up to 60 months without special treatment, as his symptoms of neck stiffness were minor and his symptom has not worsened since then. CONCLUSION: SF after CDA is a rare condition that can be attributed to patient- or prosthesis-related causes, and its risk factors are diverse. SF after CDA did not affect the patient's clinical outcome, and no special treatment was required for it. Practitioners should be aware of this rare complication and advise patients of the risks before performing CDA.

Rare Cervicothoracic Intramedullary and Extramedullary Lipoma.

We report a rare case of cervicothoracic intramedullary and extramedullary lipoma. Complete resection of the extramedullary lipoma and almost complete resection of the intramedullary lipoma were performed using a microscope, followed by posterior fusion and internal fixation from C4-T2 to maintain the stability of the cervicothoracic junction. Despite the high risk, it was still necessary to perform the decompression surgery and the surgical results were favorable.

Rare Bony Diastematomyelia Associated with Intraspinal Teratoma.

We report a rare case of bony diastematomyelia associated with intraspinal teratoma. The patient was surgically treated with bony diastematomyelia and intradural teratoma resection, followed by lumbar duroplasty, and posterior fusion from L2-L4 in order to maintain the spinal stability of the approached segments. Despite the risks, it was necessary to perform early surgical treatment because of rapid neurologic deterioration. The patient had a good postoperative outcome.

Intradural Lumbar Disc Herniation: A Case Report and Literature Review.

BACKGROUND: Lumbar disc herniation into the dural space is a very rare phenomenon of degenerative lumbar lesions in the elderly population, and its potential pathogenesis and natural course remain unclear. CASE DESCRIPTION: We describe a rare case of intradural lumbar disc herniation. A 68-year-old man presented with progressive lower back pain and radiating pain and numbness in both legs for 3 years. Magnetic resonance imaging revealed a large herniated disc at L4-L5. Posterior discectomy and fusion of the L4-L5 was performed after conservative treatment failed. Intraoperatively, only minimal disc fragments in the epidural space were found after meticulous probing following laminectomy of the L4-L5 vertebrae. The dorsal dura mater was saturated, tense, and bulged at the L4-L5 levels; additionally, an intradural mass was palpable and confirmed by intraoperative ultrasonography. Subsequently, dorsal middle durotomy was performed. Upon opening the dural sac, a large cauliflower-like mass similar to nucleus pulposus tissue was found near the arachnoid membrane. The mass was dissociative and could be completely resected. The dorsal dural incisions were closed after careful exploration, followed by fixation and fusion of the L4-L5 levels. Pathological examination revealed disc tissue with central balloon-type cystic degenerative changes. The patient's lower back pain and radiating pain and numbness of both legs improved remarkably postoperatively, and he became asymptomatic at 3 months postoperatively. CONCLUSION: Intradural lumbar disc herniation should be highly suspected when intraoperative findings are incompatible with findings from the preoperative imaging examination, and it could be further confirmed via intraoperative ultrasonography and pathological examination of the resected tissue from the dural space. Prompt surgery is recommended, and surgical results are usually favorable. We also reviewed the literature and discussed the potential pathogenesis, natural course, diagnosis, and treatment of intradural lumbar disc herniation.

LanCL1 attenuates ischemia-induced oxidative stress by Sirt3-mediated preservation of mitochondrial function.

Lanthionine synthetase C-like protein 1 (LanCL1) is homologous to prokaryotic lanthionine cyclases, and has been shown to have novel functions in neuronal redox homeostasis. A recent study showed that LanCL1 expression was developmental and activity-dependent regulated, and LanCL1 transgene protected neurons against oxidative stress. In the present study, the potential protective effects of LanCL1 against ischemia was investigated in an in vitro model mimicked by oxygen and glucose deprivation (OGD) in neuronal HT22 cells. We found that OGD exposure induced a temporal increase and persistent decreases in the expression of LanCL1 at both mRNA and protein levels. Overexpression of LanCL1 by lentivirus (LV-LanCL1) transfection preserved cell viability, reduced lactate dehydrogenase (LDH) release and attenuated apoptosis after OGD. These protective effects were accompanied by decreased protein radical formation, lipid peroxidation and mitochondrial dysfunction. In addition, LanCL1 significantly stimulated mitochondrial enzyme activities and SOD2 deacetylation in a Sirt3-dependent manner. The results of western blot analysis showed that LanCL1-induced activation of Sirt3 was dependent on Akt-PGC-1α pathway. Knockdown of PGC-1α expression using small interfering RNA (siRNA) or blocking Akt activation using specific antagonist partially prevented the protective effects of LanCL1 in HT22 cells. Taken together, our results show that LanCL1 protects against OGD through activating the Akt-PGC-1α-Sirt3 pathway, and may have potential therapeutic value for ischemic stroke.

Comparison of Percutaneous Kyphoplasty and Bone Cement-Augmented Short-Segment Pedicle Screw Fixation for Management of Kümmell Disease.

BACKGROUND The purpose of this study was to compare the efficacy of percutaneous kyphoplasty (PKP) and bone cement-augmented short segmental fixation (BCA+SSF) for treating Kümmell disease. MATERIAL AND METHODS Between June 2013 and December 2015, 60 patients were treated with PKP or BCA+SSF. All patients were followed up for 12-36 months. We retrospectively reviewed outcomes, including Oswestry Disability Index (ODI), visual analogue scale (VAS), and kyphotic Cobb angle. RESULTS VAS, ODI, and Cobb angle, measured postoperatively and at the final follow-up, were lower than those measured preoperatively in both groups (P<0.05). VAS, ODI, and Cobb angle measured postoperatively demonstrated no significant differences when compared with those measured at the final follow-up in the PKP group (P>0.05). In the BCA+SSF group, VAS and ODI at the final follow-up were lower than those measured postoperatively (P<0.05), but no significant difference was found in the Cobb angle (P>0.05). The PKP group had better VAS and ODI than the BCA+SSF group, postoperatively (P<0.05). No significant difference was found in VAS and ODI at the final follow-up (P>0.05) or the Cobb angle measured postoperatively and at the final follow-up (P>0.05) between the 2 groups. Operative time, blood loss, and hospital stay in the PKP group were lower than those in the BCA+SSF group (P<0.05). No significant difference was found in complications (P>0.05). CONCLUSIONS PKP patients had better early clinical outcomes, shorter operation times and hospital admission times, and decreased blood loss, but had similar complications, radiographic results, and long-term clinical outcomes compared with BCA+SSF patients.

Bone Cement-Augmented Short-Segment Pedicle Screw Fixation for Kümmell Disease with Spinal Canal Stenosis.

BACKGROUND This study aimed to explore the feasibility and efficacy of bone cement-augmented short-segmental pedicle screw fixation in treating Kümmell disease. MATERIAL AND METHODS From June 2012 to June 2015, 18 patients with Kümmell disease with spinal canal stenosis were enrolled in this study. Each patient was treated with bone cement-augmented short-segment fixation and posterolateral bone grafting, and posterior decompression was performed when needed. All patients were followed up for 12-36 months. We retrospectively reviewed outcomes, including the Oswestry disability index (ODI), visual analog scale (VAS) score, anterior and posterior heights of fractured vertebrae, kyphotic Cobb angle, and neurological function by Frankel classification. RESULTS The VAS grades, ODI scores, anterior heights of affected vertebrae, and kyphotic Cobb angles showed statistically significant differences between pre- and postoperative and between preoperative and final follow-up values (P<0.05), whereas the differences between postoperative and final follow-up values were not statistically significant (P>0.05). The differences between posterior vertebral heights at each time point were not statistically significant (P>0.05). Improved neurological function was observed in 12 cases at final follow-up. Three cases had complications, including asymptomatic cement leakage in 2 patients and delayed wound infection in 1 patient. CONCLUSIONS Bone cement-augmented short-segment pedicle screw fixation is safe and effective for treating Kümmell disease, and can achieve satisfactory correction of kyphosis and vertebral height, with pain relief and improvement in neurological function, with few complications.

A morphometric study of the middle and lower cervical vertebral endplates and their components.

Cervical disc arthroplasty is a common method of treating cervical degenerative disease. However, the footprints of most prosthesis dimensions are obtained from data of Caucasian individuals. Besides, there is a large discrepancy between footprints of currently available cervical disc prostheses and anatomic dimensions of cervical endplates. We aimed to detail the three-dimensional (3D) anatomic morphology of the subaxial cervical vertebral endplate, utilizing high-precision, high-resolution scanning equipment, and provide a theoretical basis for designing appropriate disc prostheses for Chinese patients.A total of 138 cervical vertebral endplates were studied. Each endplate was digitized using a non-contact optical 3D range scanning system and then reconstructed to quantify diameters and surface area for the whole endplate and its components (central endplate and epiphyseal rim). The whole endplate and mid-plane concavity depth were measured.There is marked morphologic asymmetry, in that the cranial endplate is more concave than the corresponding caudal endplate, with endplate concavity depths of 2.04 and 0.69 mm, respectively. For the caudal endplates, the endplate concavity apex locations were always located in the posterior portion (81.42%), while in cranial endplates relatively even. The central endplate was approximately 60% of the area of the whole endplate and the anterior section of the ring was the widest. From C3/4 down to C6/7 discs, the vertebral endplate gradually became more elliptical. Chinese cervical endplate anatomic sizes are generally smaller than that of Caucasians. Although Korean and Chinese individuals both belong to the Asian population subgroup, the majority of anatomic dimensions differ. Singaporean cervical endplate morphology is very similar to that of Chinese patients.We performed a comprehensive and accurate quantitative description of the cervical endplate, which provide references to shape and profile an artificial cervical disc without sacrificing valuable bone stock. To design a device with footprint as large as possible to distribute the axial load, we suggest that additional attention should be paid to the marginal rim. It is essential to specifically design appropriate disc prosthesis for Chinese patients. To fit the morphologic and biomechanical variations, we also propose that the disc prostheses for different vertebral segments should be separately designed.

Transforaminal lumbar interbody fusion versus posterolateral fusion in degenerative lumbar spondylosis: A meta-analysis.

OBJECTIVE: The aim of the study was to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) versus posterolateral fusion (PLF) in degenerative lumbar spondylosis. METHODS: A systematic literature review was performed to obtain randomized controlled trials (RCTs) and observational studies (OSs) of TLIF and PLF for degenerative lumbar spondylosis. Trials performed before November 2015 were retrieved from the Medline, EMBASE, Cochrane library, and Chinese databases. Data extraction and quality evaluation of the trials were performed independently by 2 investigators. A meta-analysis was performed using STATA version 12.0. RESULTS: Two RCTs and 5 OSs of 630 patients were included. Of these subjects, 325 were in the TLIF and 305 were in the PLF group. Results showed that TLIF did not increase the fusion rate based on RCTs (relative risk [RR] = 1.06; 95% confidence interval [CI]: 0.95-1.18; P = 0.321), but increased it based on OSs (RR = 1.14; 95% CI: 1.07-1.23; P = 0.000) and overall (RR = 1.11; 95% CI: 1.05-1.18; P = 0.001) as compared with PLF. TLIF was able to improve the clinical outcomes based on 1 RCT (RR = 1.33; 95% CI: 1.11-1.59, P = 0.002) and overall (RR = 1.19; 95% CI: 1.07-1.33; P = 0.001), but not based on OSs (RR = 1.11; 95% CI: 0.97-1.27; P = 0.129) as compared with PLF. There were no differences between TLIF and PLF in terms of visual analogue scale, Oswestry Disability Index, reoperation, complications, duration of surgical procedure, blood loss, and hospitalization. CONCLUSIONS: In conclusion, evidence is not sufficient to support that TLIF provides higher fusion rate than PLF, and this poor evidence indicates that TLIF might improve only clinical outcomes. Higher quality, multicenter RCTs are needed to better define the role of TLIF and PLF.

Tuberculous Spondylitis Following Kyphoplasty: A Case Report and Review of the Literature.

Tuberculous spondylitis of the augmented vertebral column following percutaneous vertebroplasty or kyphoplasty has rarely been described. We report an unusual case of tuberculous spondylitis diagnosed after percutaneous kyphoplasty (PKP). A 61-year-old woman presented to our institution complaining of back pain following a fall 7 days before. Radiologic studies revealed an acute osteoporotic compression L1 fracture. The patient denied history of pulmonary tuberculosis (TB) and there were no signs of infection. The patient was discharged from hospital 4 days after undergoing L1 PKP with a dramatic improvement in her back pain. Two years later, the patient was readmitted with a 1 year history of recurrent back pain. Imaging examinations demonstrated long segmental bony destruction involving L1 vertebra with massive paravertebral abscess formation. The tentative diagnosis of tuberculous spondylitis was made, after a serum T-SPOT. The TB test was found to be positive. Anterior debridement, L1 corpectomy, decompression, and autologous rib graft interposition, and posterior T8-L4 instrumentation were performed. The histologic examination of the resected tissue results confirmed the diagnosis of spinal TB. Anti-TB medications were administered for 12 months and the patient recovered without sequelae. Spinal TB and osteoporotic vertebral compression fractures are similar clinically and radiologically. Spinal surgeons should consider this disease entity to avoid misdiagnosis or complications. Early surgical intervention and anti-TB treatment should be instituted as soon as the diagnosis of spinal TB after vertebral augmentation is made.

Morphological studies of cartilage endplates in subaxial cervical region.

PURPOSE: The aim of this study was to provide morphological data of endplates for the redesign of cervical artificial disc for use in the middle and lower cervical spine (C3-C7). METHODS: Reformatted CT scans of 73 individuals were analysed. The shapes of superior endplates (SEPs) and inferior endplates (IEPs) were classified as either flat or arced. The curvature radius of the IEP and sagittal disc angle were measured in the mid-sagittal plane. The maximum transverse diameter (MTD) of the SEPs and IEP was measured in the coronal plane. RESULTS: The majority of SEPs were flat (79.5 % at C7 and 91.8-95.9 % at C3-C6). Almost all (98.6-100 %) IEPs were arced. The curvature radius has a gradually increasing trend from C3 to C6 (P < 0.05, mean 29.26 mm). There were significant differences at C3-C7 in the average sagittal disc angles (5.80°, 6.92°, 7.51°, and 8.82°, respectively; P < 0.05; mean 7.26°), the average MTDs of the SEPs (13.64, 14.42, 15.03, and 16.74 mm, respectively, P < 0.05; mean 14.96 mm) and the average MTD of the IEPs (16.77, 17.67, 19.15, and 21.66 mm, respectively; P < 0.05; mean 18.81 mm). CONCLUSION: The majority of SEPs were flat, while almost all IEPs were curved. The curvature radius of IEPs has a gradually increasing trend from C3 to C6. The average sagittal disc angles, MTDs of the SEPs and IEPs significantly increased from C3 to C7. Based on the above, the current cervical artificial disc design does not sufficiently match the morphology of cervical endplates (CEPs). This mismatch may lead to some postoperative complications of cervical disc arthroplasty.

Anterior cervical discectomy and fusion versus posterior fixation and fusion of C2-3 for unstable hangman's fracture.

STUDY DESIGN: This was a retrospective study. OBJECTIVE: To compare the efficacy and safety between anterior cervical discectomy and fusion (ACDF) and posterior fixation and fusion (PFF) for treating unstable hangman's fracture. SUMMARY OF BACKGROUND DATA: In previous clinical study, ACDF and PFF have been introduced to manage unstable hangman's fracture. However, it remains unknown which approach is superior. METHODS: Between January 2006 and May 2011, 44 patients with unstable hangman's fracture underwent either ACDF or PFF. The operation time, blood loss, surgical complications, and postoperative drainage were compared. Neurologic function was evaluated using the ASIA scale and neck pain was assessed using the Visual Analogue Scale (VAS) score. Rates of fracture heeling and bone fusion were also studied. RESULTS: Follow-up was completed for 38 patients. Twenty-four cases underwent ACDF and 14 cases received PFF. The operation was successful in all 38 cases. The mean operative time, estimated blood loss, and postoperative drainage were significantly shorter or less for the ACDF group than the PFF group (P<0.01). No surgical complication was reported in the ACDF group. Excessive bleeding due to injury to the venous plexus occurred in 3 cases in the PFF group. The VAS score in the 2 groups was significantly lower than their respective preoperative score (P<0.01), but there was no difference between the 2 groups (P>0.05). Solid fusion was achieved with no implant failure in all cases 6 months postoperatively. At the final follow-up, 8 cases with ASIA C or D grade improved to E grade. CONCLUSIONS: The anterior procedure seems to be superior to the posterior approach for unstable hangman's fracture as it is a less invasive and simpler procedure with fewer complications and is especially indicated for cases with no medullary canal in C2 pedicles and traumatic C2-3 disk herniation compressing the spinal cord.

Occipitocervical fusion: fix to C2 or C3?

OBJECTIVE: The objective of this study was to explore the differences in clinical outcome between short-segment fixation (SSF; occiput-C2) and multi-segment fixation (MSF; occiput-C2, 3). METHODS: From January 2008 to January 2012, patients who underwent surgery for instability at the occipitocervical junction were included in the study. Two different groups of surgeons using two different management options completed the surgeries. One group performed SSF, whereas the other group performed MSF. A total of 53 patients met the criteria (33 SSF, 20 MSF). Mean follow-up was 33.9 months (range, 12-62 months). Fusion was demonstrated by plain radiographs and computed tomography imaging. Neurological status, pillow neck pain, operative time, blood loss during operation, and perioperative complications were compared between the SSF and MSF groups. RESULTS: The fusion rate was 97% in the SSF group and 100% in MSF the group. There was no statistically significant difference in the fusion rate between the two groups (P>0.05). One patient (3%) in the SSF group and two patients (10%) in the MSF group experienced perioperative complications. Of the 25 patients who had neurological symptoms, 22 (88%) showed improvement after the operation in the SSF group and 14 (87.5%) of 16 showed improvement in MSF group. In addition, patients who suffered from pillow neck pain achieved varying degrees of improvement after the operation. CONCLUSION: SSF may be the better choice for treating occipitocervical instability when no subaxial instability is present. Overall, modern instrumentation can provide the stability needed for successful clinical fusion.

[EFFECTIVENESS OF ANTERIOR CERVICAL PLATE FIXATION FOR UNSTABLE Hangman FRACTURE].

OBJECTIVE: To explore the effectiveness of anterior cervical plate internal fixation in the treatment of unstable Hangman fracture. METHODS: Between May 2006 and May 2010, 42 patients with unstable Hangman fracture were treated by anterior cervical plate internal fixation. There were 30 males and 12 females with an average age of 36.5 years (range, 22-64 years). According to the Levine-Edwards classification, 25 cases were rated as type II, 15 cases as type II A, and 2 cases as type III. Eight patients had spinal cord injury. The average interval between injury and operation was 5 days (range, 3-14 days). The X-ray, CT, and MRI were done pre- and post-operatively to evaluate the cervical physiological curvature, the intervertebral disc height of C2, 3, the fracture-healing, and bone fusion. The effectiveness was evaluated using visual analogue scale (VAS) for occipitocervical pain, Neck Disability Index (NDI) for cervical spine function, and the Japanese Orthopaedic Association (JOA) score for neurological functional recovery. RESULTS: All incisions healed by first intention. No neurological deterioration or internal fixation failure was observed. All of the patients were followed up 2-5 years (mean, 3.5 years). The complications were dysdipsia in 3 cases and dysphagia in 4 cases, which alleviated spontaneously after 1 week. All the patients were almost free from occipitocervical pain and the limited cervical spine motion. Neurological function was improved in 8 cases of spinal cord injury, and complete decompression was observed in 6 cases who had spinal cord compression. The bone fusion was observed at 6.5 months on average (range, 6-8 months); the mean fracture-healing time was 10.5 months (range, 9-12 months). The VAS, NDI, and JOA scores were significantly improved at 3 months after operation and last follow-up when compared with preoperative scores (P < 0.05), significant improvement scores were achieved at last follow-up when compared with the scores at 3 months (P < 0.05). The intervertebral disc height of C2, 3, the reconstructed curvature and stability of the cervical spine, and the spine movement were good. CONCLUSION: The method of anterior cervical plate internal fixation can achieve satisfactory reduction and fusion, less complications, negligible impact on the cervical movement. So it is an ideal method to treat unstable Hangman fracture.